Method and system for locating wireless devices within a local region

ABSTRACT

A method for locating wireless devices within a local region, comprising: determining respective global locations of two or more of the wireless devices; determining whether the wireless devices are within the local region by calculating respective distances between the global locations; determining respective ranges between the wireless devices within the local region; and, determining respective relative locations of the wireless devices within the local region by triangulation using the ranges.

This application claims priority from U.S. Provisional PatentApplication No. 61/874,528, filed Sep. 6, 2013, and incorporated hereinby reference.

FIELD OF THE INVENTION

This invention relates to the field of locating systems, and morespecifically, to a method and system for locating objects within a localregion.

BACKGROUND OF THE INVENTION

Radio frequency identification (“RFID”) systems have become very popularin a great number of applications. A typical RFID system 100 is shown inFIG. 1. The RFID system 100 includes an application system 110, a reader120, and a tag 130. When the tag 130 appears in the operational range ofthe reader 120, it starts receiving both energy 140 and data 150 via itsantenna 133 from the reader 120 via its transmitter/receiver 121 andantenna 123. A rectify circuit 131 in the tag 130 collects and storesthe energy 140 for powering the other circuits (e.g., control/modulator132) in the tag 130. After collecting enough energy 140, the tag 130 mayoperate and send back pre-stored data to the reader 120. The reader 120then passes the received response data via a communications interface160 to the server system/database 111 of the application system 110 forsystem applications.

The tags 130 in RFID system 100 may be classified into passive andactive types according to the power provisions of the tags. Passive tagsdo not have their own power supply and therefore draw all power requiredfrom the reader 120 by electromagnetic energy received via the tag'santenna 133. In contrast, active tags incorporate a battery whichsupplies all or part of the power required for their operation.

A typical transmission method of energy 140 and data 150 between areader 120 and a tag 130 in a RFID system 100 is by way of backscattercoupling (or backscattering). The antenna 123 of the reader 120 couplesenergy 140 to the tag 130. By modulating the reflection coefficient ofthe tag's antenna 133, data 150 may be transmitted between the tag 130and the reader 120. Backscattering, as shown in FIG. 2, is typicallyused in microwave band RFID systems. Power P_(in) 210 is emitted fromthe reader's antenna 123. A small proportion of P_(in) 210 is receivedby the tag's antenna 133 and is rectified to charge the storingcapacitor in the tag 130 for serving as a power supply. After gatheringenough energy, the tag 130 begins operating. A portion of the incomingpower P_(in) 210 is reflected by the tag's antenna 133 and returned aspower P_(return) 220. The reflection characteristics may be influencedby altering the load connected to the antenna 133. In order to transmitdata 150 from the tag 130 to the reader 120, for example, a transistormay be switched on and off in time with the transmitted data stream. Themagnitude of the reflected power P_(return) 220 may thus be modulatedand picked up by the reader's antenna 123.

One problem with existing RFID systems is that they have limitedcapability with respect to long distance ranging or locating, that is,determining the range or location of a tag, object, or wireless devicethat is located a long distance from the reader. While the range oflocal devices may be determined with existing RFID systems, problemsremain with respect to determining how many devices are local and theirrelative locations with respect to other devices.

The positioning or locating of devices is currently performed on aglobal basis using either global positioning system (“GPS”)-based and/orWiFi-based locating methods. This information is shared with mobileapplications for various reasons (e.g., localized advertising, findinglocal businesses, mapping, sharing location between users, etc.).However, using a wireless device to find the local relative location(e.g., less than 20 meters) of another wireless device, other stationarydevices, objects, or tags within centimeters via an RFID system and/orother wireless methods has not been adequately addressed. While indoorpositioning of devices within a local region has been attempted usingBluetooth™ 4.0, such an application requires changes to the Bluetooth™standard and the need for a base-station mounted on the ceiling of thebuilding in view of the devices to be located.

A need therefore exists for an improved method and system for locatingobjects within a local region. Accordingly, a solution that addresses,at least in part, the above and other shortcomings is desired.

SUMMARY OF THE INVENTION

According to one aspect of the invention, there is provided a method forlocating wireless devices within a local region, comprising: determiningrespective global locations of two or more of the wireless devices;determining whether the wireless devices are within the local region bycalculating respective distances between the global locations;determining respective ranges between the wireless devices within thelocal region; and, determining respective relative locations of thewireless devices within the local region by triangulation using theranges.

In accordance with further aspects of the invention there is provided anapparatus such as a data processing system, a method for adapting same,as well as articles of manufacture such as a computer readable medium orproduct and a computer program product or software product (e.g.,comprising a non-transitory medium) having program instructions recordedor stored thereon for practising the method of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

Features and advantages of the embodiments of the present invention willbecome apparent from the following detailed description, taken incombination with the appended drawings, in which:

FIG. 1 is a block diagram illustrating a radio frequency identification(RFID) system in accordance with the prior art;

FIG. 2 is a block diagram illustrating transmission of energy and databetween a reader and a tag in a RFID system in accordance with the priorart;

FIG. 3 is a block diagram illustrating a data processing system inaccordance with an embodiment of the invention;

FIG. 4 is a block diagram illustrating a system for locating wirelessdevices within a local region in accordance with an embodiment of theinvention;

FIG. 5 is a block diagram illustrating the use of RFID methods todetermine the relative location of local wireless devices with respectto each other, in accordance with an embodiment of the invention;

FIG. 6 is a block diagram illustrating an application or module runningon a wireless device and an associated screen capture illustrating a mapscreen, in accordance with an embodiment of the invention;

FIG. 7 is a block diagram illustrating an application or module runningon a wireless device an associated screen capture illustrating aproperties screen, in accordance with an embodiment of the invention;

FIG. 8 is a block diagram illustrating an application or module runningon a wireless device and an associated screen capture illustrating analternate properties screen, in accordance with an embodiment of theinvention;

FIG. 9 is a block diagram illustrating an application or module runningon a wireless device and an associated screen capture illustratinganother alternate properties screen, in accordance with an embodiment ofthe invention;

FIG. 10 is a block diagram illustrating a system for locating wirelessdevices within one or more local regions in accordance with anembodiment of the invention;

FIG. 11 is a block diagram illustrating an application or module runningon a wireless device and an associated screen capture illustrating analternate map screen, in accordance with an embodiment of the invention;and,

FIG. 12 is a flow chart illustrating operations of modules within a dataprocessing system for locating wireless devices within a local region,in accordance with an embodiment of the invention.

It will be noted that throughout the appended drawings, like featuresare identified by like reference numerals.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

In the following description, details are set forth to provide anunderstanding of the invention. In some instances, certain software,circuits, structures, techniques and methods have not been described orshown in detail in order not to obscure the invention. The term “dataprocessing system” is used herein to refer to any machine for processingdata, including the computer systems, servers, wireless devices, radiofrequency identification (“RFID”) systems, and network arrangementsdescribed herein. The present invention may be implemented in anycomputer programming language provided that the operating system of thedata processing system provides the facilities that may support therequirements of the present invention. Any limitations presented wouldbe a result of a particular type of operating system or computerprogramming language and would not be a limitation of the presentinvention. The present invention may also be implemented in hardware orin a combination of hardware and software.

FIG. 3 is a block diagram illustrating a data processing system 300 inaccordance with an embodiment of the invention. The data processingsystem 300 is suitable for use in a locating system 400 as a server 407and/or wireless device 440 or in a RFID system 100 as a reader 120and/or tag 130. The data processing system 300 is also suitable forgenerating, displaying, and adjusting presentations in conjunction witha graphical user interface (“GUI”), as described below. The dataprocessing system 300 may be a client and/or server in a client/serversystem. For example, the data processing system 300 may be a serversystem or a personal computer (“PC”) system. The data processing system300 may also be a wireless device or other mobile, portable, or handhelddevice. The data processing system 300 includes an input device 310, acentral processing unit (“CPU”) 320, memory 330, a display 340, and aninterface device 350. The input device 310 may include a keyboard, amouse, a trackball, a touch sensitive surface or screen, a positiontracking device, an eye tracking device, or a similar device. Thedisplay 340 may include a computer screen, television screen, displayscreen, terminal device, a touch sensitive display surface or screen, ora hardcopy producing output device such as a printer or plotter. Thememory 330 may include a variety of storage devices including internalmemory and external mass storage typically arranged in a hierarchy ofstorage as understood by those skilled in the art. For example, thememory 330 may include databases, random access memory (“RAM”),read-only memory (“ROM”), flash memory, and/or disk devices. Theinterface device 350 may include one or more network connections. Thedata processing system 300 may be adapted for communicating with otherdata processing systems (e.g., similar to data processing system 300)over a network 351 via the interface device 350. For example, theinterface device 350 may include an interface to a network 351 such asthe Internet and/or another wired or wireless network (e.g., a wirelesslocal area network (“WLAN”), a cellular telephone network, etc.). Assuch, the interface 350 may include suitable transmitters, receivers,antennae, etc. In addition, the data processing system 300 may include aGlobal Positioning System (“GPS”) receiver or other type of positioningsystem or device. Thus, the data processing system 300 may be linked toother data processing systems by the network 351. The CPU 320 mayinclude or be operatively coupled to dedicated coprocessors, memorydevices, or other hardware modules 321. The CPU 320 is operativelycoupled to the memory 330 which stores an operating system (e.g., 331)for general management of the system 300. The CPU 320 is operativelycoupled to the input device 310 for receiving user commands or queriesand for displaying the results of these commands or queries to the useron the display 340. Commands and queries may also be received via theinterface device 350 and results may be transmitted via the interfacedevice 350. The data processing system 300 may include a database system332 (or store) for storing data and programming information. Thedatabase system 332 may include a database management system (e.g., 332)and a database (e.g., 332) and may be stored in the memory 330 of thedata processing system 300. In general, the data processing system 300has stored therein data representing sequences of instructions whichwhen executed cause the method described herein to be performed. Ofcourse, the data processing system 300 may contain additional softwareand hardware a description of which is not necessary for understandingthe invention.

Thus, the data processing system 300 includes computer executableprogrammed instructions for directing the system 300 to implement theembodiments of the present invention. The programmed instructions may beembodied in one or more hardware modules 321 or software modules 331resident in the memory 330 of the data processing system 300 orelsewhere (e.g., 320). Alternatively, the programmed instructions may beembodied on a computer readable medium or product (e.g., a memory stick,a compact disk (“CD”), etc.) which may be used for transporting theprogrammed instructions to the memory 330 of the data processing system300. Alternatively, the programmed instructions may be embedded in acomputer-readable signal or signal-bearing medium or product that isuploaded to a network 351 by a vendor or supplier of the programmedinstructions, and this signal or signal-bearing medium may be downloadedthrough an interface (e.g., 350) to the data processing system 300 fromthe network 351 by end users or potential buyers.

A user may interact with the data processing system 300 and its hardwareand software modules 321, 331 using a user interface such as a graphicaluser interface (“GUI”) 380 (and related modules 321, 331). The GUI 380may be used for monitoring, managing, and accessing the data processingsystem 300. GUIs are supported by common operating systems and provide adisplay format which enables a user to choose commands, executeapplication programs, manage computer files, and perform other functionsby selecting pictorial representations known as icons, or items from amenu through use of an input device 310 such as a mouse. In general, aGUI is used to convey information to and receive commands from users andgenerally includes a variety of GUI objects or controls, includingicons, toolbars, drop-down menus, text, dialog boxes, buttons, and thelike. A user typically interacts with a GUI 380 presented on a display340 by using an input device (e.g., a mouse) 310 to position a pointeror cursor 390 over an object (e.g., an icon) 391 and by “clicking” onthe object 391. Typically, a GUI based system presents application,system status, and other information to the user in one or more“windows” appearing on the display 340. A window 392 is a more or lessrectangular area within the display 340 in which a user may view anapplication or a document. Such a window 392 may be open, closed,displayed full screen, reduced to an icon, increased or reduced in size,or moved to different areas of the display 340. Multiple windows may bedisplayed simultaneously, such as: windows included within otherwindows, windows overlapping other windows, or windows tiled within thedisplay area.

FIG. 4 is a block diagram illustrating a system 400 for locatingwireless devices (e.g., 440) within a local region 401 in accordancewith an embodiment of the invention. The system 400 includes one or morelocal wireless devices 440 and one or more non-local wireless devices450. The system 400 also includes a server 407 communicatively coupledto the wireless devices 440, 450 over a network 351 such as an InternetProtocol (“IP”) cloud including a wireless wide area network (“WWAN”)and/or a wireless local area network (“WLAN”). Local wireless devices440 are devices that are located within a local region 401 having aradius of less than 20 meters, for example, or within a given in-doorenvironment such as a conference room, a social environment (e.g., abar, a restaurant, etc.), a meeting room, a local region of a shoppingmall, or in a house. Non-local wireless devices 450 are devices that arelocated in a non-local region 406 beyond or outside of the local region401. According to one embodiment, each of the server 407 and thewireless devices 440, 450 may include or have a configuration similar tothat of the data processing system 300.

According to one embodiment of the invention, first, the global location441 of each wireless device 440 is determined. Second, which wirelessdevices 440 are located in the local region 401 is determined from theglobal locations 441. Third, the relative location 444 of each wirelessdevice 440 with respect to each other wireless device within the localregion 401 is determined using RFID methods.

Referring again to FIG. 4, a GPS-based or WiFi-based method or system orother type of positioning system or device provides the global locationof the wireless devices 440, 450. The local wireless devices 440 shownin FIG. 4 are denoted UE1, UE2, UE3, and UE4, where “UE” means “userequipment”. The other devices (i.e., non-local wireless devices 450denoted UE5 to UEn) shown in FIG. 4 are not located within the localregion 401 and are identified or located by either GPS-based orWiFi-based methods. The respective global location 441, 451 of eachwireless device 440, 450 may be denoted by x and y coordinates (e.g.,(x1, y1), (x2, y2), . . . (xn, yn)) as shown in FIG. 4. The respectiveabsolute error in the global location of each local wireless device 440as determined by GPS-based or WiFi-based methods may be denoted by aradius (e.g., r1, r2, r3, and r4) 442 as shown in FIG. 4. These errors442 may be in the tens of meters. The global locations 441, 451 of thewireless devices 440, 450 as determined via GPS-based or WiFi-basedmethods are stored in the memory 330 of the server 407 which may becommunicatively coupled to the wireless devices 440, 450 via eithercellular or WiFi communications.

The server 407 determines which wireless devices 440 are located in thelocal region 401 by considering the global location 441 of the wirelessdevices 440 and correlating these within a relative distance less apredetermined radius. For example, the server 407 may determine whetherall of the wireless devices 440 are within a 20 metre radius (or 100metre radius, etc.). This may be done, for example, by calculatingvector differences (e.g., (x1, y1)−(x2, y2), etc.) or distances betweenthe global locations 441 of the wireless devices 440.

FIG. 5 is a block diagram illustrating the use of RFID methods todetermine the relative location 444 of local wireless devices 440 withrespect to each other, in accordance with an embodiment of theinvention. FIG. 5 shows which wireless devices 440 are local to eachother and how measurement of their relative locations 444 using RFIDmethods or RFID real-time locating methods is performed. With respect tothe use of RFID methods, which wireless device (e.g., 410) is to beconsidered as the detector and which wireless device (e.g., 420) is tobe considered as the tag may be controlled or configured via the server407 and may be communicated back to the respective wireless devices 410,420, for example, via either cellular or WiFi communications. Forexample, if a first local wireless device 410 (UE1) is initiallydesignated as the detector, then it will send out an original signal 210to all the other local wireless devices 420, 430, 440 (UE2, UE3, UE4)accordingly. The other local wireless devices 420, 430, 440 backscattermodulated signals 220 back to the first local wireless device 410. Themodulated signals 220 may include information such as wireless deviceproperties, identifications, etc. The range 443 of all of the localwireless devices 410, 420, 430, 440 may then be determined by the firstlocal wireless device 410. This information may then be sent to theserver 407. Next a second wireless device 420 (UE2) is designated as thedetector device and the range 443 of all the other wireless devices 410,430, 440 may then be determined by the second wireless device 420 (UE2).This information may again be sent to the server 407. This process maycontinue for all the other wireless devices 430, 440 or for only apredetermined or fixed number of wireless devices (e.g., 430 alone,etc.). Using triangulation, the relative location 444 of all thewireless devices 410, 420, 430, 440 may then be determined by the server407 from the range 443 information. Methods for determining relativelocations 444 other than by triangulation may also be used. Thisrelative location 444 information may then be sent to selected or all ofthe wireless devices 410, 420, 430, 440. Note that the locationdetection or determination is denoted by broken lines labelled “RTLS”(i.e., real-time locating system or real-time location service) in FIG.5.

FIG. 6 is a block diagram illustrating an application or module (e.g.,331) running on a wireless device (e.g., 440) and an associated screencapture illustrating a map screen 600, in accordance with an embodimentof the invention. On the left side of FIG. 6, the relative locations 444of the wireless devices 410, 420, 430, 440 (UE1 to UE4) in the localregion 401 are shown. On the right side of FIG. 6, a screen capture isshown which includes a map screen 600. The map screen 600 may bedisplayed on the display 340 of a wireless device 440 (UE4) by theapplication 331 via the wireless device's GUI 380 and related modules331. The map screen 600 includes a pictorial illustration,representation, or map showing the relative location 444 of each of thewireless devices 410, 420, 430, 440. Each wireless device 410, 420, 430,440 may be represented by a respective icon 610, 620, 630, 640 on themap screen 600. The icon 640 used to represent the user's wirelessdevice 440 on the map screen 600 may indicate such to the user, forexample, by using a different shape and/or text (e.g., “YOU”).

FIG. 7 is a block diagram illustrating an application or module (e.g.,331) running on a wireless device (e.g., 440) and an associated screencapture illustrating a properties screen 700, in accordance with anembodiment of the invention. If the user of the wireless device 440selects one of the wireless devices 410, 420, 430, 440 by eithertouching or clicking on the wireless device's icon 610, 620, 630, 640 onthe map screen 600, for example, various properties 710 relating to theselected wireless device (e.g., 410) may be displayed on a propertiesscreen 700 as shown in FIG. 7. The properties 710 of the variouswireless devices 410, 420, 430, 440 may be transmitted over the network351 (and/or by RFID methods) and stored in the memory 330 of the server401 to support various applications and interactions. In FIG. 7, theuser of the fourth wireless device 440 has selected the icon 610representing the first wireless device 410 and hence the properties 710relating to the first wireless device 410 are presented or highlightedon the display 340 of the fourth wireless device 440. These properties710 may include a picture, photograph, representation, or image 711 ofthe person or object associated with the first wireless device 410.Also, various actions 712 associated with the first wireless device 410may be presented. These actions 712 may include, for example, socialinformation, sending an email, sending a text, saving contactinformation, pinging the selected wireless device (e.g., 410), settingup a WiFi direct link, or setting up a Bluetooth™ link. If the wirelessdevice 410 is not associated with a person, the displayed properties,images, and actions 710, 711, 712 may be different or adjustedaccordingly. Some properties 710 may be determined by the settings ofthe wireless device 410. For example, access to the “Send msg” or sendmessage action by the surrounding wireless devices 420, 430, 440 may notbe allowed by the selected wireless device 410.

FIG. 8 is a block diagram illustrating an application or module (e.g.,331) running on a wireless device (e.g., 440) and an associated screencapture illustrating an alternate properties screen 800, in accordancewith an embodiment of the invention. In FIG. 8, the user of the fourthwireless device 440 has selected the icon 620 representing the secondwireless device 420 (UE2). In this example, the second wireless device420 is a printer. As such, the properties 810 differ from those 710included in the properties screen 700 for the first wireless device 410as shown in FIG. 7 and may include actions 812 such as setting up theprinter and printing a file. The printer name 811 or an image of theprinter may also be included on the properties screen 800.

FIG. 9 is a block diagram illustrating an application or module (e.g.,331) running on a wireless device (e.g., 440) and an associated screencapture illustrating another alternate properties screen 900, inaccordance with an embodiment of the invention. In FIG. 9, the user ofthe fourth wireless device 440 has selected the icon 620 representingthe second wireless device 420 (UE2). In this example, the secondwireless device 420 is a display or monitor. As such, the properties 910differ from those 710 included in the properties screen 700 for thefirst wireless device 410 as shown in FIG. 7 and may include actions 912such as setting up the monitor, sending a picture or image, sending avideo, and downloading remote control settings. The monitor printer name911 or an image of the monitor may also be included on the propertiesscreen 900.

FIG. 10 is a block diagram illustrating a system 400 for locatingwireless devices 440 within one or more local regions 401, 402, 403,404, 405 in accordance with an embodiment of the invention. FIG. 10shows a global view of several local regions 401, 402, 403, 404, 405 andseveral wireless devices (e.g., 440). In addition, FIG. 10 shows thevarious properties stored in the memory 330 of the server 407 for theseveral local regions 401, 402, 403, 404, 405 or subsets of the wirelessdevices 440. For example, local region “local1” 401 has three wirelessdevices 410, 440, 1000 labelled as UE, UE, and UEL. One of the wirelessdevices 1000 (UEL), shown as being located in the first local region 401(local1) in FIG. 10, may be a fixed position device configured to storeinformation relating to the relative mapping of the local region 401.Exact co-ordinates pertaining to this wireless device 1000 (UEL), whichmay be obtained from an on-board GPS receiver for example, may be sentto the server 407 to assist in computing the location of the otherwireless devices 410, 440. Again, information pertaining to selected orall the local regions 401, 402, 403, 404, 405 and their local wirelessdevices 410, 440, 1000 may be stored in the server 407. The server 407is used to determine the global location 441 of the wireless devices 440and also their relative locations 444 within each local region 401 orsubset. The server 407 may include modules 331 for tunneling informationbetween the wireless devices 440, if desired. In addition, the server407 may control the wireless devices 440 to assist in locating orcomputing the relative location 444 of all the other local wirelessdevices 440. Furthermore, the server 401 may manage mapping informationrelating to the local regions 401, 402, 403, 404, 405.

FIG. 11 is a block diagram illustrating an application or module (e.g.,331) running on a wireless device (e.g., 440) and an associated screencapture illustrating an alternate map screen 1100, in accordance with anembodiment of the invention. On the left side of FIG. 11, the relativelocations 444 of the wireless devices 410, 420, 430, 440 (UE1 to UE4)are shown. The large rectangular blocks represent walls 1401, 1402,1403, 1404. The wireless devices 410, 420, 430, 440 (UE1 to UE4) areparticular devices that may be associated with individuals, printers,monitors, or other devices. Mapping information may be stored in awireless device or RFID tag 1000 labeled UEL in FIG. 11. The fixedwireless device 1000 either defines or points to mapping information.There may be several fixed wireless devices 1000 in a given local region401. Note that only one fixed wireless device 1000 is shown in FIG. 11.The fixed wireless device 1000 may be either a passive or active RFIDtag device. On the right side of FIG. 11, a screen capture is shownwhich includes a map screen 1100. As in FIG. 6, the map screen 1100includes a pictorial illustration, representation, or map showing therelative location 444 of each of the wireless devices 410, 420, 430,440. Each wireless device 410, 420, 430, 440 may be represented by arespective icon 610, 620, 630, 640 on the map screen 600. The icon 640used to represent the user's wireless device 440 on the may screen 600may indicate such to the user, for example, by using a different shapeand/or text (e.g., “YOU”). In addition, the map screen 1100 may includea map outline 1110 which in turn may include a respective icon 1601,1602, 1603, 1604 for each of the walls 1401, 1402, 1403, 1404 appearingin the local region 401. Note that an icon for the fixed wireless device1000 is not shown on the map screen 1100 as it is generally not requiredto be shown to a user. Of course, an icon for the fixed wireless device1000 may be shown optionally.

According to one embodiment of the invention, the operations of theserver 407 described above may be incorporated in one of the wirelessdevices (e.g., 440). In such an embodiment, a server 407 would not berequired. For example, in such an embodiment, the wireless device 440would determine the relative locations 444 of the local devices 410,420, 430 around it by communicating with them via RFID methods, that is,the information stored within each wireless device (e.g., 410) may betransmitted to the other wireless devices (e.g., 420, 430, 440) usingRFID communication methods (e.g., backscattered information). Thewireless devices 410, 420, 430, 440 may also communicate using cellularor WiFi communications.

According to one embodiment of the invention, the system 400 may useradar-based RFID methods for locating wireless devices 410, 420, 430,440. In this embodiment, one or more of the wireless devices 410, 420,430, 440 includes a radar detecting device, reader, or system and one ormore of the wireless devices 410, 420, 430, 440 includes or acts as abackscattering wireless device, object or tag. The radar-based RFIDmethod used may employ relative power measurements to determine theranges 443 of the wireless devices 410, 420, 430, 440. In operation, afirst wireless device (e.g., 410) may reflect back or backscatter aunique frequency offset signal to a detecting system in a secondwireless device (e.g., 420). In addition, the wireless device 410 maybackscatter an identification (“ID”) signature (e.g., a controlledoffset frequency). By using methods such as power measurement, etc., therange 443 of the backscattering wireless device 410 may then bedetermined by the detecting system in the second wireless device 420. Interms of power measurement, the power returned P_(r) to the detectingreceiver antenna of the detecting system in the second wireless device420 is given by the equation:

$P_{r} = \frac{P_{t}G_{t}A_{r}\sigma \; F^{4}}{\left( {4\; \pi} \right)^{2}R^{4}}$

where P_(t) is the transmitting power of the detecting system'stransmitter, G_(t) is the gain of the detecting system's transmittingantenna, A_(r) is the effective aperture of the receiver antenna of thefirst wireless device 410, σ is the radar cross section, F is thepattern propagation, and R is the range 443 or distance between thefirst wireless device 410 and the second wireless device 420.Triangulation, for example, may then be used to determine the relativelocations 444. Of course, the relative location 444 of the wirelessdevices 410, 420, 430, 440 may be determined using other radar-basedmethods known to those of skill in the art.

According to one embodiment, the first wireless device 410 transmits anoriginal signal (e.g., 210) and the second wireless device 420, inresponse to the original signal 210, backscatters a modulated signal(e.g., 220) that is a frequency offset version of the original signal210. Backscattering of a frequency offset modulated signal 220 isdescribed, for example, in United States Patent Application PublicationNo. US 2014/0016719 A1, published Jan. 16, 2014, and incorporated hereinby reference.

The above embodiments may contribute to an improved method and system400 for locating wireless devices (e.g., 440) within a local region 401and may provide one or more advantages. First, the present inventionenables a local wireless device 440 to map out wireless devices 410,420, 430 located around it and to display the relative locations 444 ofthe wireless devices 410, 420, 430, 440. Second, the present inventionallows a wireless device 440 to determine and display the variousproperties 710 of the wireless devices 410, 420, 430 located around it.Third, the present invention may be used to support wireless deviceapplications such as the following: (a) determining the location oflocal printers and sending a file to them to be printed; (b) determiningthe location of monitors and sending videos or pictures to them fordisplay; (c) socializing or understanding the social situation of otherusers having wireless devices that are mapped locally (e.g., in a bar,in a conference, in a restaurant, in a business meeting, etc); and, (d)sending a message or file to a user having a wireless device that ismapped locally. Fourth, the present invention allows the location ofwireless devices to be locally determined using RFID methods inconjunction with wide area or global location services includingGPS-based or WiFi-based methods.

Aspects of the above described method may be summarized with the aid ofa flowchart.

FIG. 12 is a flow chart illustrating operations 1200 of modules (e.g.,software or hardware modules 331, 321) within a data processing system(e.g., 300, 407, 440) for locating wireless devices (e.g., 410, 420,430, 440) within a local region 401, in accordance with an embodiment ofthe invention.

At step 1201, the operations 1200 start.

At step 1202, respective global locations 441 of two or more of thewireless devices 410, 420, 430, 440 are determined.

At step 1203, a determination is made as to whether the wireless devices410, 420, 430, 440 are within the local region 401 by calculatingrespective distances (e.g., (x1, y1)−(x2, y2), etc.) between the globallocations 441.

At step 1204, respective ranges 443 between the wireless devices 410,420, 430, 440 within the local region 401 are determined.

At step 1205, respective relative locations 444 of the wireless devices410, 420, 430, 440 within the local region 401 are determined bytriangulation using the ranges 443.

At step 1206, the operations 1200 end.

In the above method, the step 1204 of determining the respective ranges443 between the wireless devices 410, 420, 430, 440 within the localregion 401 may include: transmitting respective original signals (e.g.,210) from the wireless devices 410, 420, 430, 440; in response to therespective original signals 210, receiving respective modulated signals(e.g., 220) at ones of the wireless devices (e.g., 440) from others ofthe wireless devices (e.g, 410, 420, 430), the modulated signals 220being backscattered from the others of the wireless devices 410, 420,430, the modulated signals 220 being frequency offset versions of theoriginal signals 210; and, determining the ranges 443 between thewireless devices 410, 420, 430, 440 from the modulated signals 220. Themethod may further include measuring respective powers of the modulatedsignals 220, the powers of the modulated signals 220 being inverselyproportional to the ranges 443 between the respective wireless devices410, 420, 430, 440 to the fourth power. The respective original signals210 may be transmitted sequentially from the wireless devices 410, 420,430, 440. The ranges 443 may be determined by respective radio frequencyidentification systems (e.g., 100) included in the wireless devices 410,420, 430, 440. The global locations 441 may be determined usingrespective global positioning system receivers (e.g., 321) included inthe wireless devices 410, 420, 430, 440. The respective original signals210 may be respective original radar signals and the respectivemodulated signals 220 may be respective modulated radar signals. Theranges 443 may be distances between the respective wireless devices 410,420, 430, 440. The method may further include storing the relativelocations 444 in a memory 330 of at least one of the wireless devices410, 420, 430, 440. And, the method may further include presenting therelative locations 444 on a display 340 of at least one of the wirelessdevices 410, 420, 430, 440.

According to one embodiment, each of the above steps 1201-1206 may beimplemented by a respective software module 331. According to anotherembodiment, each of the above steps 1201-1206 may be implemented by arespective hardware module 321. According to another embodiment, each ofthe above steps 1201-1206 may be implemented by a combination ofsoftware 331 and hardware modules 321. For example, FIG. 12 mayrepresent a block diagram illustrating the interconnection of specifichardware modules 1201-1206 (collectively 321) within a data processingsystem 300, each hardware module 1201-1206 adapted or configured toimplement a respective step of the method of the invention.

While this invention is primarily discussed as a method, a person ofordinary skill in the art will understand that the apparatus discussedabove with reference to a data processing system 300 may be programmedto enable the practice of the method of the invention. Moreover, anarticle of manufacture for use with a data processing system 300, suchas a pre-recorded storage device or other similar computer readablemedium or product including program instructions recorded thereon, maydirect the data processing system 300 to facilitate the practice of themethod of the invention. It is understood that such apparatus andarticles of manufacture also come within the scope of the invention.

In particular, the sequences of instructions which when executed causethe method described herein to be performed by the data processingsystem 300 may be contained in a data carrier product according to oneembodiment of the invention. This data carrier product may be loadedinto and run by the data processing system 300. In addition, thesequences of instructions which when executed cause the method describedherein to be performed by the data processing system 300 may becontained in a computer program product or software product (e.g.,comprising a non-transitory medium) according to one embodiment of theinvention. This computer program or software product may be loaded intoand run by the data processing system 300. Moreover, the sequences ofinstructions which when executed cause the method described herein to beperformed by the data processing system 300 may be contained in anintegrated circuit product (e.g., a hardware module or modules 321)which may include a coprocessor or memory according to one embodiment ofthe invention. This integrated circuit product may be installed in thedata processing system 300.

The embodiments of the invention described above are intended to beexemplary only. Those skilled in this art will understand that variousmodifications of detail may be made to these embodiments, all of whichcome within the scope of the invention.

What is claimed is:
 1. A method for locating wireless devices within alocal region, comprising: determining respective global locations of twoor more of the wireless devices; determining whether the wirelessdevices are within the local region by calculating respective distancesbetween the global locations; determining respective ranges between thewireless devices within the local region; and, determining respectiverelative locations of the wireless devices within the local region bytriangulation using the ranges.
 2. The method of claim 1 wherein thedetermining the respective ranges between the wireless devices withinthe local region includes: transmitting respective original signals fromthe wireless devices; in response to the respective original signals,receiving respective modulated signals at ones of the wireless devicesfrom others of the wireless devices, the modulated signals beingbackscattered from the others of the wireless devices, the modulatedsignals being frequency offset versions of the original signals; and,determining the ranges between the wireless devices from the modulatedsignals.
 3. The method of claim 2 and further comprising measuringrespective powers of the modulated signals, the powers of the modulatedsignals being inversely proportional to the ranges between therespective wireless devices to the fourth power.
 4. The method of claim2 wherein the respective original signals are transmitted sequentiallyfrom the wireless devices.
 5. The method of claim 1 wherein the rangesare determined by respective radio frequency identification systemsincluded in the wireless devices.
 6. The method of claim 1 wherein theglobal locations are determined using respective global positioningsystem receivers included in the wireless devices.
 7. The method ofclaim 1 wherein the respective original signals are respective originalradar signals and wherein the respective modulated signals arerespective modulated radar signals.
 8. The method of claim 1 wherein theranges are distances between the wireless devices.
 9. The method ofclaim 1 and further comprising storing the relative locations in amemory of at least one of the wireless devices.
 10. The method of claim1 and further comprising presenting the relative locations on a displayof at least one of the wireless devices.
 11. A system for locatingwireless devices within a local region, comprising: a processor coupledto memory, a transmitter, and a receiver; and, at least one of hardwareand software modules within the memory and controlled or executed by theprocessor, the modules including: a module for determining respectiveglobal locations of two or more of the wireless devices; a module fordetermining whether the wireless devices are within the local region bycalculating respective distances between the global locations; a modulefor determining respective ranges between the wireless devices withinthe local region; and, a module for determining respective relativelocations of the wireless devices within the local region bytriangulation using the ranges.
 12. The system of claim 11 wherein themodule for determining the respective ranges between the wirelessdevices within the local regions includes: a module for controlling thetransmitter to transmit an original signal from the system; a module forcontrolling the receiver to, in response to the original signal, receiverespective modulated signals at the system from the wireless devices,the modulated signals being backscattered from the wireless devices, themodulated signals being frequency offset versions of the originalsignal; and, a module for determining the ranges between the wirelessdevices and the system from the modulated signals.
 13. The system ofclaim 12 and further comprising a module for measuring respective powersof the modulated signals, the powers of the modulated signals beinginversely proportional to the ranges between the respective wirelessdevices and the system to the fourth power.
 14. The system of claim 12wherein the respective original signals are transmitted sequentiallyfrom the system.
 15. The system of claim 11 wherein the ranges aredetermined by a radio frequency identification system included in thesystem.
 16. The system of claim 11 wherein the global locations aredetermined using respective global positioning system receivers includedin the wireless devices and in the system.
 17. The system of claim 11wherein the respective original signals are respective original radarsignals and wherein the respective modulated signals are respectivemodulated radar signals.
 18. The system of claim 11 wherein the rangesare distances between the wireless devices.
 19. The system of claim 11and further comprising a module for storing the relative locations in amemory of the system.
 20. The system of claim 11 and further comprisinga module for presenting the relative locations on a display of thesystem.